Conduit-coupling device



H. G; KNODEHER. CONDULT COUPLING DEVICE. APPLICATION FILED 0CT.27, 1920.

Patented Aug. 15, 1922.

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My invention relates to means for'coupling electric conduits to conduitbodiesor outlet boxes, and it is particularly "adapted for boxes of the separable hub type. My

invention is primarily intended for use in conduit systems of the exposed type, although certain features thereof "have a broader application.

An object of m inventionis'to provide an arrangementot parts which shall facilimy; ready and rapid connection of conduits to out-let boxes. i i

A further object of my inventionisto provide an arrangement of parts which shall enable an outlet box'to be readily adjusted to any angular position withv respect to the conduit and firmly, andfrigidly clamped in such position without disturbing the connection between the conduit and hub, thereby insuring a good electrical conned tion betweenthe metal parts oi' the conduit system whenever a good mechanical connec- My invention will be better understood from the following descript on taken n connectlon'with the accompanying drawing and its scope will be pointed out in theap pended claims,

Referring to the drawing, F 1 is a side view showing thepreferr ed form of'my invention ce'rtain parts being shown "in'sec tion; Fig. 2 is an elevation of aniodiiiejd construction; Fig.3 is asectioni on the line 3+3 of Fig. 2, Fig. 4 is aside view with certain parts shown insectionof a further modification, and Fig, 5 is a perspective view with parts broken away showing the nut locking feature of F igL-4. e

Referring to F ig." 1, the outlet boxjli is provided :with i any desired, number of openings in the walls thereof for, Inaking;-.c0nduit connections thereto; well known Specification of LettersPatent. P t -htgdnAfig ii5, 1922 Application filed October-caused; SeriaI TQ- QIQflZQ Q enNnR-Ani E'LEo the art, these openingsare'customarily provided with removable closures which permit of making conduit connections at thedesired point or points in the side or bottom 'w'alls of. the box. "Such removable The box is shown as provided with separable hubs for making conduit connections to opposite sidesof the 'b'0x. The closurehas bee'nfremoved from theopening 3" in theleft c'losu'resa're indicated in the drawing at 2.

hand side of the box toenable a conduit connection to be made to the conduit 4. The conduit in this case'is smaller than the opening in the wall of the outlet box and the conduit connection is made by the reducing The" bushing 5 is internally bushing 5. i I threaded to engage the conduit 4 and is externally threaded to engage with the clamping nut 6. Thebushingb projects through the, opening in the wallof'the boxand is provided with a flange 7 located insidethe box and this flange is provided withapolygonal periphery to enable the same to be readily turned or heldin any desiredposie tion.' The bushing or outlet member 5' is also provided with afrounded internal shoulder 8 on thei same end of the; bushing as thefiange to prevent abrasion of conductors leading from the conduit into the outlet box, and; toprovide an abutment for thef end of the conduit where. the conduit has been providediwithlsuch long thre'ad that the conduit does not bind in'the co u-' against the wall of the box. These ofi'set portions inay be made by punching: a small section-fottheg r'net'al of hewang r the box, whichjniitzll is is uallyst'eel a'nd conduit. connection to be made in the desired direction. He then inserts the bushing 5 into the opening and clamps it firmly in place by the nut 6. When thus clamped in place, flange 7. engages olfset portion9- whereby the bushing 5 and the outlet box are held against turning movement relatively to each other. He then turns the box and hub together until a firm and rigid threaded connection ismade with the conduit. Ifit is then found that the box does notoccupy the desired angular relation with the conduit, he backs off the nut 6 to a slight extentand then b'y a slight endwise movement of the bushing through the box releases thelocking engagement between the bushing and the offset portion 9 of the box. The box may then'be turned to the desired position, after which the nut 6 is tightened to clamp the box firmly in place. It will be observed that in making this angular adj ustment of the box it is unnecessary to disturb the threaded connection between the outlet member 5 andlconduit, 4. Thus, whenever a goodmechanical connection is established with the box a good electrical connection is established between all the. metal parts of the conduit system. The maintenance of a good electrical, connection between these parts is of great importance since it enables all parts of the conduit system to be thoroughly grounded. If there are obstructions which closelydefine the position of the box so that it cannot be turned to make a conduit connection; the connection may nevertheless be readily made by inserting the bushing into the opening andthr eadingthe conduit into the bushing. Where two con duit systems are being connected together and the conduitcannot be turned because of a coupling made at the other end thereof, the

bushing will be turned until it firmly engages the conduit, after which the nut 6 will be turned to clamp the wall 01 the box firmly in place. The nut Gbeing accessible and thereby easily turned. enables a firm and rigid connection to be made between the conduit'and' box without the difiiculty that isexperienced in those arrangements utilizing-a clamping nut inside the box. e

The conduit connection shown at the right hand side of'the box in Fig. 1 represents a connection between a conduit 4; of a size corresponding tq the opening in the wall. oi the box. In this case the outlet member 10 is provided with a screw threaded projectionll forinsertion through the opening This outlet member is prqvided with a flange 7 provided with a polygonal head. The

wall of the outlet box is clamped between the flange 7 and the coupling member 12 which is in threaded engagement with the thereon or by the abutting of the end of the conduit against the end, of the outlet member 10. He may, if desired, however, first thread the coupling member 12 firmlyv on to the conduit 4, then insert the outlet member 10 through the opening in the wall of the box and thread it into the coupling member 12 by turning either the outlet member or the conduit and coupling member together. In either case, when the flange 7 is prevented from further turning by the offset portion 9 the coupling member-12 and conduit 4 will be turned together the slight extent necessary toclamp the wall of the box firmly in place. Upon slightly backing oil the coupling member 12, the angular position of the box may be readily adjusted as heretofore described in connection with the reducing coupling shown at the left hand side ofthe box. y Where two conduit systems are being connected together and the conduit 4' cannot be turned because of a coupling made at the other end thereof. the workman will run an extra long thread upon the conduit thus giving a few straight or untapered threads. The out-let member will then be threaded into the [coupling member until it firmly butts against the end of the conduit, after which the coupling member will be turned upon the threads of the outlet member and conduit to clamp the box firmly and rigidly in place. 'Iheabutting relation of the conduit and outlet member causes a binding acengage the polygonalhead of the outlet member' This ofiset portion 14 is preferably formed by making an inverted V-shaped cut in the wall of the box pressing the point of the V inwardly to a slight extent.- The box shown in Fig. 2 is indicated as provided with a plurality of removable closures 15 and 16 in the same wall of the "box and .the offset portion-is here solocated with respect to the openingszthat it may. perform its locking function .forv conduit connections to be 'established in either of the openings.

In the modification of my invention shown in Fig.q4, th'e.-ofi'set portion of the :wall of the boxgfor'locking'the polygonal head of the joutlet member" is made by arranging the walls of the box to meet inv a curved inner edge 17 so located as to be engaged by the corners of the polygonal flange 7 just prior to the seating of this flange against the wall of the box/ The cooperative relationship of the parts isshown more clearly in Fig. 5. A slight endwise movement of the outlet member with respect to the box permits the polygonal head to turn freely within the boX.

In connection with my invention, it will be noted that when the conduit ends are fastened to the box or boxes, the engaging means between the fastening means and the box or boxes serves to lock the conduit ends rigidly to the box or boxes. As a result a wiring installation comprising conduits and boxes embodying my inventionforms a continuous rigid conduit system in which the boxes and conduit lengths are positively locked. together a-galnst turning movement conduit ends, I form a continuous rigid con-.

duit structure which may be installed by fastening it at such points as are found most convenient.

While I have shown and described certain specific embodiments of my invention, it is apparent to those skilled in the art that modifications may be made without departing from the spirit of my invention, and I therefore aim to cover'all such modifications and variations as fall within the scope of my invention as defined in the appended claims.

lVhat I claim as new and desire to secure by Letters Patent of the United'States, is z 1. The combination of an outlet box of V the class described having an opening in a wall thereof, means for making a conduit connection to said box comprising a screwthreaded outlet member projecting through said opening and rotatable therein, said outlet member being provided with locking means rotatable therewith, the wall of the member and conduit.

box :being' provided with. an offsetj'portiou adjacent the "opening'therein adapted to engage said 'locking' means to prevent rotation of the outlet member when the outlet member approaches itsfinal-position to-complete T."

the connection. a 2; The combinationwith an outlet box of the classdescribed, of, a separable hub for -making a, conduit connectionythereto comprising-a member threaded to. engage a conduit and a member cooperating with said of the box firmly andrigidly between said members, characterized by the fact that locking means releasable upon a slightfendwise movement of they conduit engaging conduit engaging member to clamp the wall.

member is provided for holding one of said members against rotation with respect to the box in any one of a plurality of positions within the box whereby the box may be securely clamped in any desired angular rela- 1 tion to the. conduit without disturbing the threaded connectionbetween the coupling 3 8. Thecombination of an outlet boxjof the class described having an opening ma wall thereof and meansfor making a conduit connection to said box comprising a screw-threaded member having a polygonal periphery and a surface 3 adapted toengage the wall of; .the box around said openingto clamp the box inplace, characterized by the fact that the wall of the box is provided with an offset portion arranged to engage with a part "of" the polygonal periphery of the screw-threaded member and lock the same against rotation just prior to .the engagement of the clamping surface of said member with the wall of the box.

4;.The combinationof an outlet-box of the class'described having-an openingin a wall thereof for makinga conduit connection, a screw-threaded outlet member prey jecting through the opening and havin a flange provided with a polygonal head with in the box, a member having screw threads arranged to cooperate with said outlet member to seat said flange against the wall of the box to clamp the box in place, characterizedby thefact that the wall of the box is provided with an'offset portion arranged to engage with a part of the polygonal-head of the outlet member and lock the same against rotation just prior to the seating of the flange against thewall of the box.

5. An out-let box of the class described having adjacent walls'thereof substantially at right angles to each other and meeting to form a curvededge, one of said walls being provided with an opening for making a conduit connection to said box, characterized by the fact that the opening is located sufficiently close to the'inner edge of the box to permit the curved surface to act as ainuta lock for conduit securing means.

10 threads arranged to cooperate with said out let member to seat saidflan'ge; against: the

wall of the box to: clamp the box in place,

said opening in the wall of the boxbeing arranged. adjacent said curved edgeso that thewpolygonal headof. said outlet member shall. engage said curved surface to lock said" outlet member againstrotation.

In witness. whereof; I have hereunto set my hand this 26thday-of- October 1920.

. HOME-R; G. KNODERER. 

